Circulatory problems in the lower extremities are frequently seen in elderly people. These problems, sometimes precipitated by diabetes, may lead to a below-knee amputation. Following a below-knee amputation, individuals are confronted with the necessity to literally learn anew how to walk using prosthetic devices. However, using a prosthesis requires substantial strength and endurance of the proximal muscles of the residual limb and the lower trunk. Young people are more likely to possess such strength and/or to be able to develop them quickly with exercise. This is not so likely in cases of amputation in elderly individuals in whom weakness of the residual leg muscles is frequently a limiting factor that may not be amenable to exercise.
Patients after a below-knee amputation, especially the elderly, have been documented to demonstrate remaining muscle atrophy and weakness even after complete rehabilitation (Renstrom et al., 1983; Klingenstierna et al., 1990). On the other hand, it has been shown that strength of the knee extensors may be increased with special exercise (Klingenstierna et al., 1990).
Doctors, physical therapists, and athletic trainers suggest a variety of different exercises to strengthen the lower limbs and to increase the force of knee and hip muscles. Various techniques and devices have been designed to provide such exercises. However, most of these devices require a patient or an athlete to maintain a vertical posture, or to visit a gym, which is difficult for example, for an elderly person, disabled person, or a person with a leg amputation. Besides that, many patients with, for example, arthritis can not use regular devices because of joint pain during regular exercises.
When the full range of motion in the joint can not be performed because, for example, pain, isometric exercises are helpful in increasing of muscle force without moving the joint.
The present invention is intended to provide an exercise device for increasing the force of leg muscles that overcomes the problems as set forth above. The recognized benefits of the present invention are in minimizing joint compression and shearing forces by using isometric exercises. Isometric contractions for rehabilitation or physical therapy or conditioning, especially in cases of painful joints or after a joint has been fully or partially immobilized due to disease or surgery provide a means of exercise without joint motion. This is particularly important for users with impaired, e.g., painful or arthritic knee joints, or the elderly.
The device may be used at the hospital, home, health club, office, school gym, or outdoors, depending upon the purposes and result desired. It occupies relatively little space and can be operated quietly.
A number of devices are known which may be used in the performance of knee exercises. U.S. Pat. No. 4,727,860 that provides for movement about three axes that correspond to and are coaxial with the knee joint axes of flexion/extension, tibial rotation and abduction/adduction.
Another type of exerciser device includes straps attached to elastic members wherein the user's foot is firmly grasped, and the device is held in place by the user attaching it to the back of a chair with the user sitting in said chair and moving his/her knee against the tension created by the elastic member (U.S. Pat. No. 4,478,414, U.S. Pat. No. 4,844,454). However, such devices can not provide isometric exercises.
A further type of exerciser provides movements of the boards when the user puts his feet on boards (U.S. Pat. No. 4,862,875). However, such a device does not allow a user to provide isometric contraction of muscles.
Another type of exerciser device has been disclosed which is attached to the limb of the user and the position of the biasing member can be changed between a first position and a second position directly opposed to the first position, thereby providing a resistive force against which different muscles of the limb work (U.S. Pat. No, 5,013,037). However, such a device has to be attached to the user's limb. This is not possible in the case of amputation.
Another type of exerciser device has been developed which is designed to exercise abductor/adductor leg muscles. The device is based on applying force against the tension created by the elastic member (U.S. Pat. No. 5,480,367) or cabled weight assembly (U.S. Pat. No. 5,562,578). However, such devices do not provide isometric training of leg muscles.
For background purposes and as an indicator of the state of the art to which the invention relates references may be made to the following remaining patents found in the search: U.S. Pat. No. 5,324,241, U.S. Pat. No. 5,284,131, U.S. Pat. No. 4,784,121, U.S. Pat. No. 5,575,743.
Other References
Klingenstierna U, Renstrm P, Grimby G, Morelli B. (1990) Isokinetic strength training in below-knee amputees. Scand J Rehab Med 22: 39-43.
Renstrom P, Grimby G, Gustavsson E. (1983) Thigh muscle strength in below knee amputees. Scand J Rehab Med 15, Suppl. 9: 163-173.
Therefore a need exists for a leg exerciser that has the versatility to enable a user to produce a broad range of knee and hip, exercise isometrically on patients who have lost part of their leg.
The present invention can provide a wide spectrum of exercises with a different range of angles in the knee and hip joints. The device may be easily adjusted to variations in size, age, medical conditions, and training level of the individual.
The present invention can furnish an isometric type of muscle contraction, which provides an exercise effect on the knees and hips; it causes the muscles in the legs to flex and contract; it may tend to strengthen and develop these muscles after only a relatively short period of practice.
The present device can be used for training of elderly and disabled people, rehabilitation of injured knee and hip joints, and fitness and body fat reduction programs and for patients with residual limbs following amputation.